Electrical discharge lamps, in particular high intensity discharge (HID) lamps are widely used today, e. g. in vehicle headlights. While first generations of such automotive HID lamps comprised a lamp base only for mechanical mounting and electrical contacting of a burner, currently developed lamps include circuitry for operation and/or ignition of the burner integrated within the lamp base.
Some components, which may be used e. g. for delivering a high voltage for ignition of an arc discharge within the burner require special electrical insulation. For especially good electrical insulation, electrical components, in particular a transformer, have been “potted”, i. e. embedded within a surrounding insulation compound.
US 2010/0134010 A1 describes a gas discharge lamp with a burner fixed to a lamp base consisting of electrically conductive or metalized plastic, or by plastic enclosed in an electrically conductive casing, e. g. made from aluminum, magnesium or brass. The base is closed by a base plate consisting of a material well conductive thermally as well as electrically, such as aluminum or magnesium. In the interior of the base, ignition electronics including an ignition transformer and operation electronics are provided. An electrically conductive shielding surface is established between the ignition electronics and the operation electronics by a metallic sheet inserted between two circuit boards, connected to the electrically conductive casing. Remaining hollow chambers within the casing, in particular around the ignition transformer, are filled with a casting compound to prevent electrical flashover due to the high voltage created by the ignition transformer, and also for de-heating of the electronics and for providing a mechanically sturdy unit.